class_docstr: Class that enables tracking of the maximum memory utilization on a
  system.
  
  This creates a thread which samples the available memory every sample_interval_s
  seconds. The "available" memory is reported directly from psutil.
  See https://psutil.readthedocs.io/en/latest/#psutil.virtual_memory for more
  information.
code: def __init__(self, sample_interval_s: float):
      self._results = {}
      self._stop_event = threading.Event()
      self._print_updates = False
  
      self._thread = threading.Thread(
          target=self._track_memory_utilization,
          args=(
              sample_interval_s,
              self._print_updates,
              self._results,
              self._stop_event,
          ),
      )
  
file_path: ray/release/air_tests/air_benchmarks/mlperf-train/metric_utils.py
imports: import threading
  import time
label_desc: Use image node_id 1 to create a new MaxMemoryUtilizationTracker object  with example: obj = MaxMemoryUtilizationTracker(sample_interval_s)